xfs: Check for extent overflow when adding dir entries

Source kernel commit: f5d92749191402c50e32ac83dd9da3b910f5680f

Directory entry addition can cause the following,
1. Data block can be added/removed.
A new extent can cause extent count to increase by 1.
2. Free disk block can be added/removed.
Same behaviour as described above for Data block.
3. Dabtree blocks.
XFS_DA_NODE_MAXDEPTH blocks can be added. Each of these
can be new extents. Hence extent count can increase by
XFS_DA_NODE_MAXDEPTH.

Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>

diff --git a/libxfs/xfs_inode_fork.h b/libxfs/xfs_inode_fork.h
index bcac769a7df6fddf9baca65f294cbfb2388c448c..ea1a9dd8a76326f641785257cf8ec2a0ce6e8b6b 100644 (file)
--- a/libxfs/xfs_inode_fork.h
+++ b/libxfs/xfs_inode_fork.h
@@ -47,6 +47,19 @@ struct xfs_ifork {
  */
 #define XFS_IEXT_PUNCH_HOLE_CNT                (1)
 
+/*
+ * Directory entry addition can cause the following,
+ * 1. Data block can be added/removed.
+ *    A new extent can cause extent count to increase by 1.
+ * 2. Free disk block can be added/removed.
+ *    Same behaviour as described above for Data block.
+ * 3. Dabtree blocks.
+ *    XFS_DA_NODE_MAXDEPTH blocks can be added. Each of these can be new
+ *    extents. Hence extent count can increase by XFS_DA_NODE_MAXDEPTH.
+ */
+#define XFS_IEXT_DIR_MANIP_CNT(mp) \
+       ((XFS_DA_NODE_MAXDEPTH + 1 + 1) * (mp)->m_dir_geo->fsbcount)
+
 /*
  * Fork handling.
  */